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Finding the Fourth Proportional to 263.80, 395.67 and 81.21

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Solution

The fourth proportional to 263.80, 395.67 and 81.21 is: 121.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    263.80 : 395.67 = 81.21 : x
  2. Step 2: Convert to fraction form
    263.80/395.67 = 81.21/x
  3. Step 3: Cross multiply
    263.80x = 395.67 × 81.21
  4. Step 4: Simplify right side
    263.80x = 32,132.36
  5. Step 5: Solve for x
    x = 32,132.36/263.80
  6. Step 6: Final answer
    x = 121.81

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.